"I am very excited to create a new collection that bears my name. Now more than ever, with London being at the forefront of fashion, it feels like I'm back home working with Topshop".

Topshop's Green: Product is the key to sales

Philip Green, owner of Arcadia Group, tells CNBC that if you've got great product people will shop with you.

Moss previously designed for Topshop between May 2007 and November 2010, creating a number of sell-out ranges. Her collections were launched to much fanfare, and on one occasion stopped traffic when Moss herself posed in the windows of Topshop's Oxford Street flagship store in London.

The model is a personal friend of British retail tycoon Philip Green, who heads up the Arcadia Group of retailers which owns Topshop. He said he was "thrilled" by Kate's return, adding that she had been "sorely missed."

"The Topshop business has developed extensively around the globe since we launched with Kate in 2007, and it's our intention to launch and sell this collection in all 40 countries world-wide where Topshop has a presence, in addition to creating pop-ups in department stores around the globe," Green said in a press release.

The retailer, which has 319 stores in the U.K., has been expanding steadily over the last few years, and now has 137 franchises across the world.

Speaking at London Fashion Week last month, Green told CNBC that the chain was focusing on rolling out flagship stores and boutiques within big department stores, which were "win-win" for the shops involved.

Topshop launched a store in Hong Kong in June, and has four stand-alone outlets in the U.S. -- in Chicago, New York, Las Vegas and Los Angeles. It has continued to expand in America by opening concessions inside Nordstrom department store.